diff --git a/web/src/lib/canvas/canvas-project-generation.ts b/web/src/lib/canvas/canvas-project-generation.ts
index 6d545f728..627b770b6 100644
--- a/web/src/lib/canvas/canvas-project-generation.ts
+++ b/web/src/lib/canvas/canvas-project-generation.ts
@@ -373,7 +373,10 @@ export function buildGenerationConfig(config: AiConfig, node: CanvasNodeData | u
     const storedModel = resolveCanvasGenerationModel(config, node?.metadata?.model, mode);
     const preferredModel = storedModel || resolveCanvasGenerationModel(config, defaultModel, mode) || fallbackModel;
     const imageSize = mode === "image" ? node?.metadata?.size || config.size || defaultConfig.size : undefined;
-    const model = resolveCompatibleModel(config, preferredModel, imageSize ? { ...requirements, imageSize } : requirements) || preferredModel;
+    // 无 requirements 的调用（重试、媒体工具等）也按当前能力与尺寸路由到组内最低价兼容模型，
+    // 避免旧 metadata.model 不支持当前尺寸导致生成时被 normalize 回退。
+    const baseRequirements = requirements?.capability ? requirements : { capability: mode };
+    const model = resolveCompatibleModel(config, preferredModel, imageSize ? { ...baseRequirements, imageSize } : baseRequirements) || preferredModel;
     const imageProfile = mode === "image" ? modelCapabilityConfigFor(config, model).image! : undefined;
     const normalizedImage = imageProfile
         ? normalizeImageValue(imageProfile, {
diff --git a/web/src/lib/model-selection.ts b/web/src/lib/model-selection.ts
index 2afc949a7..7621a0f7d 100644
--- a/web/src/lib/model-selection.ts
+++ b/web/src/lib/model-selection.ts
@@ -50,30 +50,35 @@ export function configuredModelDisplayName(config: AiConfig, value: string) {
 
 export function modelCompatibilityError(config: AiConfig, model: string, requirements?: ModelRequirements) {
     const capability = requirements?.capability;
+    if (!capability) return "";
     const input = requirements?.input;
-    if (!capability || !input) return "";
-    const visualInputCount = input.imageCount + input.characterCount;
+    const visualInputCount = input ? input.imageCount + input.characterCount : 0;
 
     if (capability === "image") {
+        const image = modelCapabilityConfigFor(config, model).image!;
+        // 尺寸兼容不依赖输入摘要：无输入时（如画布重试/工具链）也要按尺寸过滤组内模型。
+        if (requirements.imageSize && !image.size.allowCustom && !image.size.values.includes(requirements.imageSize)) return "不支持当前尺寸";
+        if (!input) return "";
         if (input.videoCount > 0) return "图片模型不支持参考视频";
         if (input.audioCount > 0) return "图片模型不支持参考音频";
-        const image = modelCapabilityConfigFor(config, model).image!;
         if (visualInputCount > image.references.maxImages) return `最多支持 ${image.references.maxImages} 张参考图`;
-        if (requirements.imageSize && !image.size.allowCustom && !image.size.values.includes(requirements.imageSize)) return "不支持当前尺寸";
         return "";
     }
 
     if (capability === "video") {
         const profile = modelCapabilityConfigFor(config, model).video!;
+        if (requirements.videoSeconds && !videoDurationAllowed(profile, Number(requirements.videoSeconds))) return "不支持当前视频时长";
+        if (!input) return "";
         if (visualInputCount > profile.references.maxImages) return `最多支持 ${profile.references.maxImages} 张参考图`;
         if (input.videoCount > profile.references.maxVideos) return `最多支持 ${profile.references.maxVideos} 个参考视频`;
         if (input.audioCount > profile.references.maxAudios) return `最多支持 ${profile.references.maxAudios} 个参考音频`;
-        if (requirements.videoSeconds && !videoDurationAllowed(profile, Number(requirements.videoSeconds))) return "不支持当前视频时长";
         const operation = resolveVideoOperation(input, requirements.videoOperation);
         if (operation !== "concat" && !profile.operations.includes(operation)) return `不支持${videoOperationLabel(operation)}`;
         return "";
     }
 
+    if (!input) return "";
+
     if (capability === "text") {
         return input.audioCount > 0 ? "文本模型不支持参考音频" : "";
     }